1. Field of the Invention
This invention relates to the precise correction of imbalance of rotating shafts and more particularly to new and improved methods and machines having the capability to automatically determine the imbalance of a rotating shaft, determine the amount of weight variance needed for shaft balancing and subsequently effecting such change at precise points on the shaft in predetermined and widely varying balance-correcting planes thereof.
2. Description of Prior Art
Balancing machines with fixed weld guns for attaching balancing weights to workpieces have been devised to measure and correct for imbalance in various rotating components such as driveshafts or propshafts used in automotive vehicles. Such balancing weights are normally welded to the shafts in balancing planes associated with nearby Cardan or other misalignment joints of the shafts. Ideally, such weights are positioned to completely balance the inertia forces of the rotating shaft. Rotational balancing is needed to reduce or eliminate vibration of the mechanical system using such driveshafts to improve occupant comfort and to reduce forces on shaft bearings and other automotive components to thereby enhance the service life or durability of such equipment.
While these balancing machines have provided many important and useful benefits, they usually have one weld gun unit for each plane of correction. Generally, two weld gun units are required for weight balancing one-piece driveshafts, three weld gun units for balancing two-piece driveshafts and four weld gun units for balancing four-piece driveshafts. Each weld gun unit of the machine is manually set up to a correcting horizontal position in an associated predetermined first correction plane extending across the central axis of the driveshaft to be balanced on the machine. After the shaft is rotated and imbalance is determined, balancing weights are subsequently welded to shaft by the discrete gun units in the associated first correction planes.
If further shaft balancing is needed, each weld gun unit may be capable of limited horizontal or longitudinal adjustment restricted to a second correction plane that is only a small and predetermined distance from the first correction plane. This adjustment may automatically take place when additional weight needs to be added to the shaft in the second unbalance correction plane to balance the shaft. Such multiple guns including those with fine adjustment are expensive and add to the costs, complexity and difficulty in balancing driveshafts.
In addition to the welding of imbalance correcting weight at predetermined points in correction planes of the drive shaft for shaft balancing, the physical removal of material of the shaft by cutting or milling away portions thereof with power tooling has effectively met some shaft balancing goals. Such material removal for weight adjustment for balancing purposes of shafts such as a drive shaft is tedious and labor intensive and quite difficult to accomplish while ensuring shaft integrity.
In any event the prior equipment and processes do not meet new and higher standards for improved automatic shaft imbalance detection, mobility in positioning weld guns or weight removal equipment as well as new and higher goals for improved economy in capital equipment cost and operation, and in balanced parts produced.
This invention provides new and improved rotatable shaft balancing methods and machines featuring innovative mobile or infinitely adjustable balancing weight welding guns or shaft material removal mechanisms. The shaft balancing machines of this invention are automated and optimized for improved economy and greater flexibility in shaft balancing equipment and particularly in the extended linear mobility of such equipment. This equipment includes (1) welding guns that are automatically and precisely positioned to weld balancing weights on rotatable shafts in more than one widely-spaced balancing plane thereof and (2) material removal tools similarly positioned to eliminate unbalancing masses in the shaft at balancing planes thereof for optimizing shaft balancing.
An object, feature and advantage of this invention is to provide new and improved dynamic rotatable shaft balancing machines with flexible welding gun capability to reduce the requirements for additional welding guns married to particular welding planes.
Another object, feature and advantage of the present invention is to provide new and improved rotatable shaft balancing procedures and constructions having a wide range of weld gun movements including movements to an infinite number of horizontally-spaced, balance-correcting planes associated with the flexible or other constructions used for shaft connections and mountings and subsequently welding shaft balancing weights to the shaft at points at the balance correcting planes.
Another object feature and advantage of this invention is to provide new and improved methods and equipment for determining imbalance correction weights and positions for weight attachment for balancing rotating drive shafts and the like using at least one weight applying and welding gun for automatically welding balancing weight at varying horizontally spaced points on the shaft including points in widely spaced correction planes extending through the shaft and adjacent opposite ends thereof.
Another object, feature and advantage of the present invention is to provide new and improved methods and equipment for automatically determining, applying and welding imbalance correction weights at calculated balancing positions on a rotatable shaft at predetermined balance correction planes extending through a rotatable driveshaft assembly using only an optimal number of weld guns each automatically controlled and moved to and from positions at which such weights are welded to the shaft.
Another object feature and advantage of this invention is to provide new and improved rotatable shaft balancing methods and equipment for automatically determining the mass that has to be removed at the points on the shaft, the precise location where such mass is to be removed on a rotationally imbalance shaft and then to automatically remove such mass to effect shaft balancing.
These and other features, objects and advantages of this invention will become more apparent from the following specifications and drawings: